Description

The upper surface of the body of the first rib is marked by two shallow grooves, separated from each other by a slight ridge prolonged internally into a tubercle, the scalene tubercle, for the attachment of the Scalenus anterior; the anterior groove (groove for subclavian vein) transmits the subclavian vein, the posterior (groove for subclavian artery) the subclavian artery and the lowest trunk of the brachial plexus.

This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).